The HLA/Immunogenetics Laboratory, directed by Dr. Elizabeth Trachtcnbcrg at Children'sHospital & Research Center at Oakland (CHRCO), will take the role as KIR Genotyping Core Laboratory to examine the heterogeneity of KIR and role of K1R-HLA associations in unrelated blood and marrow transplantation outcome. The CHRCO HLA/Immunogenetics Laboratoryis a California State licensed clinical histocompatibility and immunogenetics laboratory with CLIA, JCHAO, ASHI and C'APaccreditation. The CHRCO HLA/Immunogenetics Laboratory director and personnel are experienced with high-throughput, high complexity genetic analyses and assay development, and have the necessary quality control and quality assurance expertise to fulfill this role. In the first year, the Laboratory will begin the KIR genotyping using established molecular methods, including PCR and sequence-specific oligonucleotidc (SSO) probeprotocols which have been validated in-house for locus-specific KIR genotyping. The PCR and SSO probe methcdology has been used successfully in the Trachtenberg Laboratory for more than ten years to type many thousands of samples at different immunogenetic loci, including the Human Leukocyte Antigen (HLA)class1 and 11 genes, and more recently the KIR gene complex. Concomitantly, the KIR Genotyping Core Laboratory will finish validation of a novel, higher-throughput single nucleotide polymorphism (SNP)-based method for genotyping the KIR loci using matrix-assisted laser desportion/ionization time-of-flight (MALD1-TOF) mass spectrometry. The accuracy, efficiency and cost-effectiveness of each typing method will then be examined to deternine which method will be used for the bulk of the genotyping in subsequent grant years. The KIR Genotyping Core Laboratory will be responsible for high-throughputKIR genotyping of 7,2<)0 transplant samples (3,600 donor-recipient pairs) in a time-frame necessary to serve the needs of;hree projects in the program, including Program Projects directed by Drs. Parham, Miller and Weisdorf. As an added level of quality assurance of typing data, atleast 15% of samples will be typed in duplicateby two laboratories (Trachtenberg and Parham), and any discrepancies will be resolved. No other Program laboratory is as sufficiently prepared to provide the rapid KIR genotyping and quality assurance measures necessaryto adequately serve the typing needs of these projects.